The invention relates to a drive wheel for a transmission drive device. Furthermore, the invention relates to a transmission drive device having a housing which is configured to receive a drive wheel.
FIG. 1 shows a perspective longitudinal section through a drive wheel 100 according to the prior art. The drive wheel 100 has a hub region 101 with a hub opening 102 via which the drive wheel 100 can be mounted on an axle (not shown) in a housing of a transmission drive device. Also apparent is an extension 103, formed in the hub region 101, with an external toothing 104, wherein the external toothing 104 on the extension 103 serves to connect the drive wheel 100 for conjoint rotation to an element to be driven, for example a cable drum of a window winder drive in a motor vehicle. The drive wheel 100 is driven by an electric motor at least indirectly via a toothing 105 on a toothed-rim region 106. The toothed-rim region 106 is connected to a disk-like intermediate region 112 via a reinforcing ring 110 that is arranged between the hub region 101 and the toothed-rim region 106 and extends radially about a longitudinal axis 108. The two opposite end sides 113, 114 of the intermediate region 112 are formed in a substantially planar manner. Furthermore, the wall thickness s of the intermediate region 112 between the hub region 101 and the reinforcing ring 110 is substantially constant. Optionally, thickened portions 115 are formed in the region of the two end sides 113, 114, the wall thickness s of the intermediate region 112 being increased in the region of said thickened portions 115, wherein the thickened portions 115 are formed for example in a circular manner.
The drive wheel 100 has two bearing points 121, 122, spaced apart from one another with respect to the longitudinal axis 108, for axially mounting the drive wheel 100. One bearing point 121 is formed by an end face 123, radially encircling the longitudinal axis 108 in an annular manner, on an intermediate ring 125 protruding from the plane of the intermediate region 112. Furthermore, the drive wheel 100 has two bearing points 126, 127 that serve for radial mounting. What is essential here is that the bearing point 121 extends radially, with respect to the longitudinal axis 108, outside the two bearing points 126, 127 that serve for radial mounting, and is arranged on the intermediate ring 125.
A drive wheel 100 according to the prior art, as described, meets the requirements placed on the drive wheel 100 with regard to required strength, wear etc. in a satisfactory manner, but has a relatively high material requirement and thus a relatively high weight.